455 olds poppin

[kcsteck]

Im drivin my 455 olds these last weekends and its gettin worse and worse. sounds like it popin out exhaust or carb ...really cant tell. its breakin up at about 4k RPM sounds like crap. I have 280 Comp cam in it but never went with stiffer springs. Is it possible im stretchin valve springs more and more every weekend or somethin and I need to install stiffer springs or somethin??couple weeks ago it would cruise 4700 rpm no problem now it sounds like crap around 4000 im a little confused. plugs look somewhat ok def not rich maybe on the leaner side but not that bad. Im runnin demon 750 carb 80 primary 85 secondary jets,Victor intake ,headers,K heads etc.timed at 8 intial and 24 mechanichel on a unilite.
any clues
casey

[GofastRacer]

I have 280 Comp cam in it but never went with stiffer springs.
Check your springs and compare it to what the timing ticket says, I'll lay odds you need to change them!..

[HotDogz]

I believe CompCam recommends a double spring setup for the 280. I dont think stock will work correctly. Valves may be floating.

[QuickJet]

And if the springs check out ok, odds are you have a cam that's going south.

[rrrr]

Adjust the dwell and timing.

[SmokinLowriderSS]

The only time I had this problem, I had a coil going bad anda failing under load. Started aBout 4k and got worse over a couple weeks down to 2700. Was fine cold but make a hard WFO blast and about 20 secconds it would fall on it's face, missing all over till I brought the revs down.

[kcsteck]

I just putt a brand new coil on it (MSD Blaster 2) fact this was first trip with it. def was worse this weekend then last weekend. I did take timing down -4 from week before as well . last week I had 12 intial and this week I tried 8. I have Unilite 9000 distributer that can not change mechanical advance. I called Mallory last week and asked and they said factory set them up at 24 degrees full advance. I was tryin to get total advance with intial around 32 degrees. maybe that is to little.Maybe this mallory dist is crap? and does not get the 24 degrees?I got it brand new in the box on ebay. Maybe it was tried and didnt work correct so they sold to me?? Ive been chasin this bad running thing for a while. tried coils carbs,jetting,timming,etc.im so bummed! im readdy to sell!

[RICHARD TILL]

dont sell. you`re doing the right thing by going thru the process of elimination. and even if springs are`nt your problem, a new set that matches your cam will be an improvement.

[BBC4Me]

I know this sounds too simple, but have you changed the spark plugs? (just a thought)

[SmokinLowriderSS]

dont sell. you`re doing the right thing by going thru the process of elimination. and even if springs are`nt your problem, a new set that matches your cam will be an improvement.
True. IMO, whenever you buy a cam, you need to get a set of springs that is intended to match the cam. That is why I bought the springs in my cam Kit that was in it and not a separate set of springs, even if it would have saved me a few bucks.

[kcsteck]

yeh I will look into the springs. I checked valve adj and on #3 cylnder the exhuast valve when not under tension is real loose (I mean almost fall off loose) and I can get it tighten down like rest when not under tension? Maybe I adjusted valves incorrectly from the start or somethin? what is correct way? I read somewhere to torque rocker arm bolts to like 35 or 25 pounds and thats what I did. did I do properly? or is there a certain method? sorry such a noob on the Olds I really only know chevy stuff.
Casey

[marty722]

I had and replaced almost everything and found out it was ths altenator. It was puting out some but not enough.... 3.8 to 4G it would start to pop.... Rebuilt Altenator and now the popping has gone away. Just my 02 cents to check the cheap and simple stuff first.....

[Big Boys Toy PE857]

I hope it's something simple for you..... but, anytime I've had that popping back through the carb. it's been a camshaft missing a lobe.

[kcsteck]

found it! cam lobe gone! lifter wore at angle like 1/16 diff from one side to other side.put on flat surface looks like the leaning tower of pizza! so how did it happen? I had put the cam and lifters in winter went maybe 5 trips and its gone. I had new lifters in oil over night etc before installing. I guess I dont know how to adjust them. I was told to torque them at 35lbs period. nothin about not being off came lobe then tighten or anything. I need to know correct way to tighten.I know how to do chevy,is it like that?
Casey

[Bubbajet]

You should check the cam gear and dist gear for wear. If the teeth are starting to get sharp, you might have cam walk, you can also look at the block where the shoulder of the cam behind the timing chain gear rides, and see if there is wear there. I have delt with that problem before. Mondello has a bronze spacer that will help prevent future cam walk. Happy Olds'ing :)

[RICHARD TILL]

maybe now is time for the cam you`ve allways wanted. make sure the new lifters rotate easily in the bores.